University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Dissertations and Theses in Biological Sciences Biological Sciences, School of 7-2011 The Complexities of Wolf Spider Communication Exploring Courtship Signal Function in Rabidosa rabida Dustin J. Wilgers University of Nebraska - Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/bioscidiss Part of the Life Sciences Commons Wilgers, Dustin J., "The Complexities of Wolf Spider Communication Exploring Courtship Signal Function in Rabidosa rabida" (2011). Dissertations and Theses in Biological Sciences. 31. https://digitalcommons.unl.edu/bioscidiss/31 This Article is brought to you for free and open access by the Biological Sciences, School of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Dissertations and Theses in Biological Sciences by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. THE COMPLEXITIES OF WOLF SPIDER COMMUNICATION: EXPLORING COURTSHIP SIGNAL FUNCTION IN RABIDOSA RABIDA by Dustin J. Wilgers A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy Major: Biologcal Sciences (Ecology, Evolution, & Behavior) Under the Supervision of Professor Eileen A. Hebets Lincoln, Nebraska July, 2011 THE COMPLEXITIES OF WOLF SPIDER COMMUNICATION: EXPLORING COURTSHIP SIGNAL FUNCTION IN RABIDOSA RABIDA Dustin J. Wilgers, Ph.D. University of Nebraska, 2011 Advisor: Eileen A. Hebets Evidence of signal complexity is seemingly pervasive across animal communication systems. Exploring signal function may provide insight into how these displays evolved and are maintained. This dissertation examines the courtship signal function in a grassland wolf spider. Rabidosa rabida lives in an extremely complex environment, and males use complex displays incorporating both visual and seismic modalities. Using several approaches I provide insight into the content and efficacy of the various signal components, as well as how variation in these displays influence female mating decisions in isolation and combined. First, I manipulated male and female body condition using diet quantity manipulations and performed mate choice trials using females of each diet across two different age classes. Female mate choice decisions varied with diet and age. Overall, younger females were choosy, mating more often with good condition males, while older females mated indiscriminately. Next, to determine which signal components may be useful in female mate assessment, I explored the condition-dependence of the signal components and tested their efficacy by performing mate choice trials in environments that differed in modality transmission. Both visual and seismic components are condition-dependent, and are sufficient to maintain copulation success when detected in isolation. Thus, each signal component may serve as both a content- and efficacy-backup when facing variable sensory environments. Lastly, I manipulated both foreleg ornamentation and the seismic display, and presented them to females both in isolation and combined, to determine if and how variation in each component influences female mating decisions. Females were choosy based on the seismic display alone, and only discriminated males based on foreleg ornamentation when detected along with a seismic signal, suggesting an inter-signal interaction. Together, these experiments suggest that the sources of selection acting on male R. rabida are just as complex as the courtship displays used during mating interactions. The courtship signal components making up the display appear to function by maintaining both copulation success and mate assessment across a variety of environments encountered. iv ACKNOWLEDGMENTS: This experience is one that I will forever remember because of all the incredible friendships and moments I have shared with everyone I have met here. I have learned something unique from each and every person I have associated with at UNL and I could not have accomplished this without you. I would like to specifically thank everyone in the Hebets’ machine. I especially thank the post-docs I have shared an office with over my time, Roger Santer and Laura Sullivan-Beckers, who provided tremendous guidance along with some much needed comic relief. The other past and present members of the lab, Aaron Rundus, Rodrigo Willemart, Kasey Fowler-Finn, Steve Schwartz, Mitch Bern, Malcolm Rosenthal, Paul Shamble, Dan Wickwire, Jason Stafstrom, and Matt Hansen all made work fun each and every day. I learned so much about science and how to do it from all of you. However, I can’t thank our fearless leader, Eileen Hebets, enough, whose work ethic as a fellow parent and commitment to my success inspired me to be a better scientist. Eileen served so many roles while I was here, including advisor, mentor, and teacher. However, her friendship is something I’ll cherish most of all. Thanks for always being there to talk about anything. Thanks to my committee members, Alexandra Basolo, William Wagner, Robert Gibson, and John Flowers, having this many fantastic minds thinking about my work is something I will never experience again. In addition to all the wonderful interactions and feedback from these colleagues and mentors, numerous people helped me with my research and maintenance of the spiders I collected. Thanks especially to Brian Cook, Dan Wickwire, and Jessica Campbell for all your help. All of this wonderful support was priceless in my v academic journey here at UNL, but as I quickly found out, in order to stay sane I needed balance in my life. I am so glad to be a part of an active lab that enjoyed having fun. Our many social events provided a much-needed distraction from the stresses of being a graduate student. Thanks to Kasey, Mitch, and Eileen for convincing me that running actually was a great stress-reliever. You have all converted me for life! Thanks to my neighbors Nate and Mindy Knott for our incredible conversations nearly every evening, the great camping trips, and best of all our annual track meet that will continue on. I would like to thank the Nebraska Cornhusker football team for a wonderful 4-hour distraction every Saturday during the fall. The five years of having season tickets has spoiled me for life. Last but definitely not least, I would like to thank the ultimate balance in my life, my family. Thanks to my wife, Autumn, for her ultimate patience with me on my academic journey. Thanks for all the help raising our wonderful kids. I know how hard you worked being not only a full-time worker, but also a full-time student, and a full-time mom. I will never forget it and I owe you more than you will ever know. Thanks to my children, Noah and Hannah, for their patience with me as a distracted Dad. Thanks to Noah for helping me feed spiders and most of all staying busy and allowing me to work when you came to visit my office (see Appendix). This has been an unbelievable journey and I couldn’t have done it without each and every one of you. vi TABLE OF CONTENTS INTRODUCTION to the THESIS...........................................................................1 CHAPTER 1: TITLE...............................................................................................9 Abstract.....................................................................................................10 Introduction...............................................................................................11 Materials and Methods..............................................................................14 Results......................................................................................................19 Discussion.................................................................................................22 Acknowledgments.....................................................................................30 Tables.......................................................................................................31 References...............................................................................................34 Figures......................................................................................................40 CHAPTER 2: TITLE.............................................................................................43 Abstract.....................................................................................................44 Introduction...............................................................................................45 Materials and Methods..............................................................................48 Results......................................................................................................56 Discussion.................................................................................................59 Acknowledgments.....................................................................................64 Tables.......................................................................................................65 References................................................................................................67 vii Figures......................................................................................................72 CHAPTER 3: TITLE.............................................................................................76